An object in flight that spins around an axis that is not aligned with its direction of travel is subject to the Magnus effect.
As an object in motion spins, the part of the object that is spinning into the oncoming air creates a small area of high pressure. Conversely, the part of the object that is spinning away from the oncoming air creates an area of low pressure. The areas of low pressure and high pressure produce a vectored force that can cause an object in flight to alter its direction. This movement is known as the Magnus effect in fluid dynamics. The Magnus effect enables cylindrical or tubular projectiles, when given sufficient linear and rotational velocities, to achieve lift and to move in a generally looping fashion.
In the toy industry, the Magnus effect has been implemented to affect interesting projectile flight patterns. The problem with existing technologies is the complexity of use. For instance, mechanisms that require wrapping a projectile with an elastic cord or string require hand and eye coordination that is beyond the skillset of many children and adults. In addition, elastic cords or strings are not easily aligned in the center of such a projectile. As a consequence, the projectile can easily be launched off-balance, destroying the necessary aerodynamic conditions and ruining the desired looping effect.